Sliding glass doors for showcases are known that are arranged on running tracks. They are conveniently offset relative to each other in the depth direction. The glass doors are engaged in rectilinear section members referred to below as ferrules, that form narrow straight strips below the glass.
Locks suitable for this type of showcase exist in two types. Firstly there are electromagnetic locking devices that are entirely suitable in terms of a pleasing appearance for such doors, but that are suitable for luxury applications only since the cost of such devices is particularly high. Secondly there are mechanical locking devices that are much less expensive, but not very attractive. Mechanical devices include locks with racks that are very visible and impede the transparency of the structure, since they are fixed to the glass, often in the middle of the door. Locks that pass through both glass doors via their metal ferrules avoid any need to machine the glass, but they are often constituted by a block inserted in a telescopic body on a spring that becomes ejected on unlocking with a key, thereby releasing the rear door from the front door. Such a device is particularly bulky and forms a staged cylindrical projection typically extending about 30 millimeters (mm) perpendicularly from the front ferrule, even in the locked position.
The presence of such a projection and the unattractive appearance of the lock are generally not suitable for making showcases for use in luxury stores where clean lines and great transparency are desired.